In the past a number of inventions have been directed to a variety of systems to provide an early warning braking signal. Of these, a number have been directed towards apparatus attached to the accelerator rather than the conventional switch triggered by the brake pedal so that the signal will be even upon, for example, release of the accelerator pedal rather than on the positive actuation of the brake pedal. This potentially provides a slightly, yet distance-travelled-wise significantly earlier signal over the conventional system where a foot is moved from the accelerator pedal onto the brake pedal.
Early braking signals reliant on a light actuation circuit parallel to the normal brake switched brake light signal circuit which are actuated from a sensor on or involved with the accelerator pedal so as to provide an advance warning of imminent braking has been disclosed in a number of published patent specifications. Examples include U.S. Pat. Nos. 3,911,394, 3,912,892, 3,921,750, 4,034,338, 4,788,526, 4,894,652; Canadian Patent Specification No. 1265593; French Patent Specification No. 2225007 and 2597810; European Patent Specification No. 219858; Australian Patent Specification No. 8664272 and German Patent Specification Nos. 3240527 and 4022856.
Many of the patent specifications aforesaid as well as the twenty two patent specifications cited against U.S. Pat. No. 4,788,526 disclose an advance warning system instead of and/or in addition to the normal brake light signalling system. Many require foot movement or foot removal from the accelerator so as to actuate an electrically or mechanically operated switching mechanism. Some relate to all braking.
A feature of many of the prior art systems referred to in any of the aforementioned patent specifications (the full content of which are hereby herein corporated by way of reference) are unsuitable for non-automatic gear changes in motor vehicles or else are so restricted in their operation as to provide advance warning for very sudden stopping only.
U.S. Pat. Nos. 4,788,526 and 4,894,652 (Eckstein and Shapira) discloses an interesting prior art advance braking warning system. That of U.S. Pat. No. 4,788,526 relies on a bellows type sensor mounted on the accelerator pedal which, during normal driving, is pressed down to a minimum volume but which, upon abrupt release, develops a sub-pressure which is used to switch a parallel brake light circuit to that normally operated by the brake pedal itself and the lights so actuated remain on until the light circuit is taken over by the brake pedal switching circuit. An alternative disclosed is a magnetic coil surrounded by an induction coil. Such a system, however, has certain disadvantages including the fact that it is appropriate for sudden braking only particularly with non-automatic gear shift vehicles and it does require a significant foot movement in order to operate the switching mechanism.
The subsequently developed embodiment of Eckstein and Shapira disclosed in U.S. Pat. No. 4,894,652 retains the bellows type mechanical actuation of a switching mechanism or the alternative of a magnetic coil surrounded by an induction coil. Again, such a system requires a significant foot movement and is inappropriate for other than automatic gear shift vehicles unless it is restricted to very sudden stopping indeed. An embodiment of the invention disclosed therein requires a switch 41 to cater for gear changes thereby removing any benefits that might have accrued from the use of the bellows which, unlike many other sensor systems on accelerators, is not dependent on a foot removal from the accelerator but rather on the change in the pressure being applied on the accelerator.
Nevertheless, all such systems have no application in a situation where manual gear shifts, which are the predominant types of gear shift used in New Zealand, are to be used and/or where the parallel system for brake signalling is to be used other than for sudden stop.